1. Field of the Invention
The present invention relates to methods for quantitatively analyzing asbestos in vermiculite-containing materials, and more specifically, involves water such as a deionized water or a weak acid. The acids may include mineral acids or organic acids. Such acids preferably include acids selected from the group consisting of HCl, HBr, HCrO4, H2SO4, and HNO3, and organic acids including citric acid, acetic acid, and formic acid. The wash and a low temperature ash process with efficient elimination of certain constituents of the vermiculite-containing materials that would otherwise obscure detection, to permit the material to be concentrated, and permit accurate determination of asbestos content. In other embodiments, after the ash process, the specimen is subjected to a concentrated acid reflux followed by a high base reflux
2. Description of the Prior Art
It has long been known that exposure to asbestos creates a high risk of cancer in those exposed. As a result of an enormous amount of older buildings having employed asbestos-containing materials prior to awareness of this cancer risk, a serious problem exists with respect to determining if vermiculite-containing insulation and fireproofing materials contain asbestos at such a level as to present a health risk. Asbestos present in such building materials may pose a risk to not only those who are regularly present in the environment, but also those engaged in remediation to remove potentially hazardous asbestos containing vermiculite-containing materials. In addition, disposal of asbestos-containing material (ACM) is regulated and imposes significant disposal costs.
In the interest of health considerations, as well as economic considerations, it is important to determine (a) which vermiculite-containing materials contain a level of asbestos such that the material should be removed from the building or the building demolished and (b) the processes by which it is removed and disposed of.
New York State has issued guidelines regarding vermiculite-containing materials. The guidelines are currently present at <http://www.wadsworth.org/labcert/elapcert/forms/Vermiculite%20Guidance_Rev08 2712.pdf>. New York, in this guideline, has stated that building materials with more than 10% vermiculite will be presumed to be asbestos containing materials (“ACM”) and must comply with certain notification and work practices. It further stated that there is a non-rebuttable presumption that there are no reliable sampling protocols for determining asbestos content in vermiculite.
Various means for preparing samples for analysis by various types of apparatus have been known.
U.S. Pat. No. 5,004,920 discloses a method of preparing membrane filters for viewing particles or fibers captured on the filters using transmission electron microscopy. This patent discloses the mounting of a section of the membrane filter on a glass slide with retention being effected by a liquid which will not release the filter when the slide is immersed in a solvent. The filter section is then coated with carbon to replicate the surface of the membrane filter and the particles and fibers thereon. The slide is then immersed in a selected solvent which attacks the filter material and causes the carbon film squares to float off of the membrane filter.
Prior art teachings regarding quantifying asbestos in a specimen of vermiculite-containing materials do not provide the level of sensitivity or precision to meet current requirements. Among other things, the prior art tends to fail to identify and quantify chrysotile, amosite, crocidolite, tremolite, actinolite, and anthophyllite, and other amphibole asbstiforms.
The Environmental Laboratory Approval Program Certification Manual under the subject “Transmission Electron Microscope Method for Identifying and Quantitating Asbestos in Non-Friable Organically Bound Bulk Samples” dated Nov. 22, 2006 item 198.4 discloses the use of ashing to eliminate organic materials followed by a concentrated hydrochloric acid wash infiltration. The high acid levels in this procedure would also preclude it from being employed in current protocols. See also item no. 198.6.
The United States EPA published an outline of a float process to separate vermiculite from mineral fibers which sink. Research Method for Sampling and Analysis of Fibrous Amphibole in Vermiculite Attic Insulation; Method 600/R-04/004; January 2004.
It is also been suggested to use a fluidized bed asbestos segregator which is a sample preparation instrument that utilizes air elutriation to separate asbestos from heavier matrix particles deposited these onto a filter which can then be analyzed by transmission electron microscopy or other microscopic techniques.
Despite the foregoing teachings, there remains a very real and substantial problem in connection with obtaining quantitative analysis of asbestos in vermiculite containing materials in accordance with current standards.